In the performance testing of smoke detectors or other devices, it is necessary to repeatably generate a consistent amount of smoke and solid particulate resulting from the smoldering of a target material, such as a foam or wood material. In the past, open sources of heat, such as cigarettes or heat wires, were used to initiate smoldering of the target material. However, the open source typically generated inconsistent amounts of smoke and solid particulate, which made repeatable testing difficult. In response, radiant heat sources were employed to initiate smoldering in target materials. One or more radiant heat sources were typically positioned offset from and directly above a target material to provide some consistent amount of heat to the target material, and more consistency in smoke and particle generation was achieved. However, because the radiant heat sources were positioned directly over the area to be heated, the resulting rising smoke and particles contacted the radiant heat sources. Such contact resulted in inconsistency in the generated heat, failure of the radiant heat sources, and even fires caused by the igniting of the particulate.
To prevent contact with the smoke and particulate, the radiant heat sources were positioned to be remote from the generated smoke and particulate. For example, four radiant heat sources were positioned at right angles to form a square shape that formed a perimeter around the target material. The resulting smoke and particulate would rise in the space between the radiant heat sources, thereby eliminating the problems associated with direct contact. The radiant heat sources were fixed to a structure that supported them in the square-shaped configuration, and adjusting the position of the radiant heat sources to adjust heat intensity was difficult or impossible. Moreover, the square-shape provided non-uniform heating in the target material, resulting in inconsistent smoke generation.